#include<stdio.h>
#include<math.h>
int main()
{
    float x;
    double y;
    printf("Please input x:");
    scanf("%f",&x);
    if(x<3)
    {
        y = 1.2;
    }
    else if(x>3)
    {
        y = 2*x+1;
    }
    else
    {
        y = 10;
    }
    printf("y=%.3lf\n",y);
}